Package opalsPreprocess

The package opalsPreprocess deals with the analysis of raw ALS data and the derivation of 3D point clouds. opalsPreprocess povides modules for the decomposition of full waveform ALS data and for (direct) georeferencing of the raw scan data based on Global Navigation Satellite System (GNSS) and Inertial Measurement Unit (IMU) data. Furthermore, additional modules deal with the derivation of additional point attributes like surface normals, echo ratio, roughness measures and the like, to be used as input in subsequent processing steps (segmentation, classification, filtering, DTM interpolation ...)

Please note, that opalsPreprocess is only partially available

Scripts and Modules of Package opalsPreprocess
Python Scripts Description
opalsPreprocess.py Package script providing tools for preprocessing of ALS data.
preAttribute.py Computes a set attributes for a list of point cloud files.
preCalcFootprint.py Calculates the axes of the laser footprint on the target using a trigonometric approach.
preCutting.py Cuts an ODM/Raster file using one or more polygons of a shape file.
preOutlierDetection.py Detects and classifies outliers within a point cloud.
preTileManager.py Provides multiple stratagies for tiling of large datasets.
preTiling.py Tesselates a (flight) block into tiles of equal size.
Modules Description
AddInfo Inserts or updates ODM attributes by combining existing attributes and/or grid models.
Bounds Derives and stores the 2D boundary polygon of a region covered by the point data of an ODM or the valid pixels of a raster.
Colorize
DirectGeoref Transforms points from scanner coordinates into geo-referenced coordinates by applying the sensor model (flight trajectory, mounting parameters).
EchoRatio Derives and stores the echo ratio (ER) attribute for points of an OPALS data manager.
Export Exports vector data stored in an OPALS data manager (ODM) in various data formats.
Fullwave Performs decomposition of the full waveform signal and provides 3D coordinates (scanner system) and additional attributes for each return.
Histo Derives histograms and descriptive statistics (min, max, mean, r.m.s, etc.) for ODM or grid/raster data sets and stores the results graphically (SVG) and numerically (XML).
Import Loads vector and raster data into an ODM for subsequent use in modules dealing with point cloud and line related data.
Info Extracts and reports header information of a vector or raster file (ODM, GDAL).
Normals Estimates local surface normal vectors for each point of a specific point cloud (ODM).
PointStats Derives and stores statistical parameters describing the local distribution of a point attribute for each point of an ODM.
RadioCal Performs radiometric calibration of ALS data and calculates physical quantities (backscatter cross section/coefficient, reflectance) for each return.
Rasterize Performs vector-to-raster conversion for all types of simple feature geometries (points, lines, polygons).
Segmentation Provides methods for point cloud segmentation based on local homogeneity using either a generic region growing approach or an adapted region growing for plane extraction.
TIN Creates a TIN surface from ODM vector data based on a 2D constrained Delaunay triangulation.
Translate Performs format conversion for vector data files with additional read support of GDAL rasters.
Vectorize Performs raster-to-vector conversion and exports polyline geometries.
View Provides an interactive 3d viewer for points (including arbitrary attributes) and lines.
ZColor Derives color coded visualizations of grid models and stores them as geo-coded raster images.